Formulating CO2 Emission Calculation Rules for the Entire Software Lifecycle to Promote Low-Carbon Software Business

NTT Advanced Technology Corporation (NTT-AT; Headquarters: Shinjuku, Tokyo; President: Tadashi Ito), as part of its efforts toward decarbonization in the software sector, has participated in and contributed to the 'Decarbonization Research Group for the Software Sector' of the Japan Environmental Management Association for Industry (JEMAI). Through this, the company has formulated CO2 emission calculation rules covering the entire lifecycle of software products. These rules enable the calculation of CO2 emissions associated with the procurement, development, operation, and disposal of software products in accordance with the Ministry of Economy, Trade and Industry's 'Carbon Footprint Guidelines.' This achievement extends the scope of CO2 emission calculations—previously limited to the procurement and development phases—to the entire lifecycle, including operation and disposal. This will facilitate the promotion of green procurement and the enhancement of corporate value for software developers, operators, and purchasers through improved Scope 3 reporting.

Leveraging 30 years of expertise and experience in LCA consulting, NTT-AT led proposals for the formulation of these rules and fostered consensus among research group members. Moving forward, the company will continue to develop these rules to contribute to the realization of a sustainable society.

1. Background With the advancement of AI development and utilization, there is growing concern regarding the environmental impact of the ICT industry. The sustainability of AI technology and data centers, which are composed of software, is receiving significant attention. While software itself does not consume physical resources, it indirectly increases energy consumption through the use of clouds, data centers, networks, and user terminals, thereby affecting the environmental impact of the entire ICT sector. Furthermore, there is increasing social demand for companies to disclose Scope 3 emissions, making the disclosure of CO2 emissions attributable to software products increasingly important for procurement evaluations and business decisions.

In March 2024, a 'Cradle-to-Gate' version of the calculation rules (v1.0) was established under the Ministry of Economy, Trade and Industry's project to support the formulation of product-specific carbon footprint calculation rules for GX promotion, enabling the evaluation of CO2 emissions during development. However, since software products are typically used for long periods after development, evaluating CO2 emissions across the entire lifecycle, including operation and disposal, remained a challenge.

2. Results of this Initiative In the JEMAI Decarbonization Research Group for the Software Sector, we have established 'Cradle-to-Grave' calculation rules that expand the scope of the previous rules from procurement and development to the entire lifecycle. These rules enable the calculation of CO2 emissions from procurement, development, operation, and disposal based on the Ministry of Economy, Trade and Industry's 'Carbon Footprint Guidelines,' establishing a foundation for formulating strategies to reduce software-related CO2 emissions and promoting the greening of the entire supply chain.